Field of Invention
The present invention relates to a bearing unit of a turbocharger. More particularly, the present invention relates to a bearing unit of a turbocharger which prevents a lubricant from leaking to an electric motor while carrying axial load of a rotary shaft in a center housing of an electric turbocharger.
Description of Related Art
In general, a turbocharger is a device that turns a turbine using exhaust gas from an engine and then increases the output of the engine by supplying high-pressure air into a combustion chamber, by operating the compressor using the torque of the turbine.
Electric turbochargers, which can operate a rotary shaft of the turbochargers with an electric motor, thus operating a compressor with the electric motor at low-speed and operating the compressor by using torque of a turbine turned by exhaust gas at high-speed, are used in recent years.
In the electric turbochargers, high-temperature heat is generated by high-speed rotation of the electric motor, the compressor wheel, the turbine wheel, and the rotary shaft, and they are cooled by a lubricant for cooling and lubricating.
In particular, the rotary shaft is cooled by the lubricant supplied into the center housing and a sealing bracket is disposed at a space at a side in the center housing where the electric motor is disposed, such that the lubricant is prevented from leaking to the electric motor.
Further, a thrust bearing carrying axial load of the rotary shaft and an oil deflector guiding the flow of the lubricant are disposed between the sealing bracket and the center housing.
However, since the sealing bracket, the thrust bearing, and the oil deflector are disposed in a line on the rotary shaft, the rotary shaft needs to be long, and accordingly, the entire length of the turbochargers is long.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.